CGM File Format – Computer Graphics Metafile Explained

CGM, short for Computer Graphics Metafile, is a standardized graphics file format used for storing and exchanging two-dimensional technical graphics. CGM files are often found in engineering documentation, technical illustrations, electronic manuals, aerospace documentation, manufacturing systems and legacy CAD-related workflows.

Typical CGM file extension: .cgm
Format type: 2D vector and mixed vector/raster graphics
Common use: technical illustrations, engineering documentation and electronic manuals

What Is a CGM File?

A CGM file contains graphical instructions used to describe a two-dimensional image. Instead of simply storing pixels like a bitmap image, CGM can describe lines, curves, shapes, text, colors and other graphical elements. This makes the format useful for technical drawings and illustrations where accurate scaling, printing and conversion are important.


CGM files may contain vector graphics, raster image data and text. Because of this, CGM is often described as a metafile format: it stores information needed to recreate or render a picture rather than being limited to one simple image representation.

Where Is the CGM Format Used?

CGM has been used in several industries where technical graphics must remain accurate and portable between different systems. Although newer formats such as PDF, SVG and DXF are more common in many modern workflows, CGM is still found in legacy archives and specialized documentation systems.

Common CGM Use Cases

  • Technical illustrations
  • Engineering documentation
  • Electronic parts catalogs
  • Illustrated parts manuals
  • Aerospace and defense documentation
  • Manufacturing and maintenance manuals
  • Legacy CAD and documentation workflows

Why CGM Was Useful

  • Device-independent 2D graphics exchange
  • Support for scalable vector graphics
  • Suitable for precise technical drawings
  • Can include text and raster elements
  • Standardized format for long-term technical documentation

What Is WebCGM?

WebCGM is a profile of the CGM standard designed for electronic documents and web-based technical graphics. It was created to make CGM more useful for interactive technical documentation by supporting features such as object identification, linking and structured technical illustrations.


WebCGM has been especially relevant for illustrated parts catalogs, technical manuals and other documentation systems where users need to interact with detailed technical graphics.

CGM Compared with PDF, SVG and DXF

CGM is not as commonly used today as PDF, SVG or DXF, but it still appears in many technical archives. Each format has a different purpose:

For many users, the most practical solution is to convert CGM files to a more widely used format such as PDF, TIFF, PNG or another image/document format.

View, Print and Convert CGM Files with ViewCompanion Standard

ViewCompanion Standard can open CGM files and convert them to commonly used formats such as PDF, TIFF, PNG, JPEG and other supported output formats. This is useful when you need to view, print, archive or share CGM technical graphics without requiring the original software that created the files.

Learn more about ViewCompanion Standard

What Can ViewCompanion Do with CGM Files?

ViewCompanion is a viewer and converter for technical document and drawing formats, including CGM and WebCGM files. It helps users open, inspect, print and convert CGM graphics on Windows without requiring the original authoring application.

View and Inspect CGM Files

  • Open CGM and WebCGM files in Windows
  • Zoom and pan technical illustrations
  • Display vector graphics with high precision
  • Inspect technical drawings and documentation graphics
  • Print CGM drawings and illustrations

Convert CGM Files

  • Convert CGM to PDF
  • Convert CGM to TIFF
  • Convert CGM to PNG
  • Convert CGM to JPEG
  • Batch convert multiple CGM files

Useful for Legacy Documentation Workflows

Many organizations still maintain archives containing CGM technical graphics, maintenance manuals, illustrated parts catalogs and engineering documentation. ViewCompanion helps modernize these workflows by making older CGM files easier to access, share, print and convert into more widely used formats such as PDF and TIFF.


Batch Conversion and Automation

ViewCompanion supports batch conversion of CGM files, allowing users to process multiple drawings or illustrations in one operation. This can be useful for document migration projects, archive conversion, engineering document management systems and organizations that need to standardize older technical files into modern formats.

Benefits of Converting CGM Files

Converting CGM files can make older technical graphics easier to use in modern workflows. For example, a CGM drawing can be converted to PDF for documentation, TIFF or PNG for image-based workflows, or another format for archiving and distribution.

CGM File Format FAQ

What is a CGM file?

A CGM file is a Computer Graphics Metafile used for storing and exchanging two-dimensional graphics. It can contain vector graphics, text and, in some cases, raster image data.


What does CGM stand for?

CGM stands for Computer Graphics Metafile.


Is CGM a vector file format?

Yes. CGM is mainly used as a vector graphics format for technical drawings and illustrations. However, the format may also contain raster image data and text.

Where are CGM files used?

CGM files are commonly found in technical illustration, engineering documentation, aerospace, manufacturing, defense, electronic manuals and legacy CAD-related workflows.


What is WebCGM?

WebCGM is a profile of the CGM standard designed for scalable technical graphics in electronic documents and web-based documentation systems.


Can CGM files be converted to PDF?

Yes. ViewCompanion can open CGM files and convert them to PDF and other supported formats.


How can I open a CGM file in Windows?

You can open CGM files in Windows using a compatible CGM viewer such as ViewCompanion.


Related Information

You may also be interested in other technical file format pages:

ViewCompanion Information

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Note: The exact CGM features supported by a file may depend on the application that created it and the CGM/WebCGM profile used.